CD4 and infection: Here, we reveal the presence of a TCRαβ+CD8α-NK1.1-CD4+GzB+ T cell population, which represents around 30% of the CD4+ T cells in the spleen of C57BL/6 (B6) mice, in the acute phase of infection with T. cruzi (Figure 1A and B and Figure 1—figure supplement 1A).